Field of the Invention
The present invention relates to a radiation-sensitive resin composition, a resist pattern-forming method, a polymer, and a method for producing a compound.
Discussion of the Background
Upon irradiation with exposure light such as an ArF excimer laser beam or a KrF excimer laser beam, chemically amplified radiation-sensitive resin compositions generate an acid from an acid generator at a light-exposed site, and a reaction catalyzed by the acid causes a difference in rate of dissolution in a developer solution between a light-exposed site and a light-unexposed site, thereby forming a resist pattern on a substrate.
Along with the advance of microfabrication technologies, such radiation-sensitive resin compositions are demanded not only to have a superior resolution, but also to be capable of forming a highly accurate pattern that is advantageous in e.g., having a rectangular cross-sectional shape, and a small line-width-roughness (LWR) which is an indicative of a variation of the line width of the resist pattern. To address the demand, incorporation of various polar groups into a polymer contained in the radiation-sensitive resin composition has been investigated, and it is known that incorporation of a lactone ring such as a norbornanelactone ring or a γ-butyrolactone ring can improve adhesiveness while maintaining favorable sensitivity, resolution, and the like (see Japanese Unexamined Patent Application, Publication Nos. 2000-26446, 2000-159758, H10-207069, and H10-274852).
However, in these days when microfabrication of resist patterns has reached the level of a line width of no greater than 40 nm, the radiation-sensitive resin compositions are demanded not only to be further superior in the resolution and the rectangularity of the cross-sectional shape, but also to exhibit a superior depth of focus (DOF), and it is also demanded that a further accurate pattern can be formed in a high process yield.